Nondestructive readout memory



March 30, 1965 R. s. wElsz ETAI.

NONDESTRUCTIVE READOUT MEMORY Filed July 25, 1962 /fEA/.WA/ deca/ff)INVENTORJ' Arroz/VFW United States Patent O kThis invention relates tomagnetic data-storage systems and, more particularly, to improvementstherein.

In an lapplication for United States Letters Patent by lRaymondStuart-Williams, Serial No. 48,885, iiled Aug. 1l, 1960, and now U.S.Patent No. 3,162,845 which is assigned to a common assignee, there isdescribed a Magnetic Information-Storage Device. This memory maycomprise a plate of magnetic ferrite material, which has 'a 4rectangulargrid of grooves laid out on one surface thereof. A first set of wires,each of which extends in a different groove along one oo-ordinate of thegrid, is designated as drive wires. A second set of wires, each of`which extends in a different groove along the other coordinate of therectangular grid, is designated as sense wires.

` Should a current be applied to one of the drive wires, no voltages areinduced in any of ythe sense wireswhich intersect it, yin view of thefact that the wires intersect one another at right angles,and,'therefore, .the lines of flux which are established by currenttiowing in the drive wire are not cut by the sensing wires. However,should a piece of ferrite material be placed as a bridge along adiagonal at the intersection of a drive line and a sense line, then thebridging material serves to distort the path of any lines of flux which`are established by a current in the drive line, so that the sense linewill be cut by these lines of ux and a voltage will be induced therein.The polarity of the voltage which is induced in the sensing wire, andthus the data which is stored, is determined by the orientation of thebridging magnetic ferrite material. That is, if it isA disposed alongone diagonal at the intersection of `a sense and drive line, the voltagewill have one polarity. If it is disposed along the opposite diagonal,'then the-polarity ofthe induced voltages are reversed.

. This type of memory can also store data by using the presence orabsence of a bridging member to represent the data stored, but the othermethod of operation is preferred.

Anr object of this invention is to provide an improved construction forthe type of nondestructive readout memory which has been described.

' Another object of the present invention is the provision of a memoryof the type described wherein the entry of data and the change of datais simplified.

Still another object of the present invention is to providey .a simplearrangement of the type described which is simplier to manufacturethanits predecessor.

These and other objects of the invention may be achieved in anarrangement employing a magnetic ferrite plate having a rectangular grido-f grooves on one of the surfaces. Drive lines are placed in the slotsor grooves along one co-ordinate of the grid, and sensing lines areplaced in the grooves along the other co-ordinate. Thus far, thestructure is the same as has been described in the previously referredto application by Raymond Stuart- Williams. A plastic plate,substantially the size of the ice ferrite plate, has holes situated suchthat each hole opens on a different intersection of the grooves in theferrite plate, when the plastic and ferrite plates are brought together.A plug of any suitable plastic material, which is sized to fit into oneof the holes in the plastic plate, is provided for each hole. Each oneof these plugs has embedded therein a bridging member, also made ofmagnetic ferrite material. The plugs are all inserted into the holes inthe plastic plate, and the plastic plate is brought in Contact with theferrite plate in a manner so that the ferrite members carried by theplugs will bridge the opposed intersections on the ferrite plate. Thus,entry of data into the memo-ry is simply achieved by properly orientingthe plugs in the holes in the plastic plate and bidging the platetogether in contact with the ferrite p ate.

The novel features that are considered characteristic of this inventionare set forth with particularity in the appended claims. The inventionitself, both as to its organization and method of operation, as well asadditional objects and advantages thereof, will best be understood fromthe following description when read in connection with the accompanyingdrawings, in which:

FIGURE 1 is a plan view of the appearance of a nondestructive readoutmemory employing a grooved ferrite plate, shown for the purpose ofproviding a better understanding of this invention;

FIGURE 2 is an enlarged section of a portion of FIG- vURE 1;

FIGURE 3 is an isometric view of an embodiment of the invention; and

FIGURE 4 is an isometric view of a plug which is employed with thisinvention.

FIGURES 1 and 2 of the drawings herein are shown in the previouslymentioned application by Raymond Stuart-Williams, for a MagneticInformation-Storage Device. FIGURE l shows a plan view of a memory, andFIGURE 2 is an enlarged section of a portion of the memory shown inFIGURE 1. This memory comprises a magnetic ferrite plate 10, which hasgrooves or slots 11A, 13A, 15A, 11B, 13B, 15B laid down in a rectangulargrid. As shown in the enlarged section of FIGURE 2, for convenience inmaintaining the wires separated from each other, the grooves which runalong one co-ordinate are not as deep as the grooves which run along theother coordinate. The rectangular grid of grooves provide a plurality offerrite lands, respectively 12A, 14A, 16A, 18A, 12B, 14B, 16B, 18B,etc., which are separated from one another by these grooves. Wires,respectively 20, 22, 24, are respectively laid in the grooves 11B, 13B,15B. Wires, respectively 30, 32, 34, are respectively laid in theorthogonally'disposed groves 11A, 13A, 15A. The wires 20, 22, 24 havedrive currents selectively applied thereto from addressing circuits 26.The Wires 30, 32, 34 are each connected topa different sensing orvoltage-detecting circuit, respectively 40, 42, 44.

FIGURE 2 shows an :enlarged cross section of an intersection-forexample, the one which may be defined by the lands 14C, 16C, 14D, and16D. The line 24 crosses the intersection in one direction, and the line32 passes Ior-thogonally thereto. Should a pulse of current be appliedto the line 24 from the selecting current source 26, no voltage Would beinduced in the line 32, unless the magnetic ux which is generated by thecurrent flowing through the line is `distorted so that it will cut ltheline 32.

Such ux distortion is provided by means of a magnetic bridging member50, lwhich extends between two diagonally positioned lands at theintersection. The bridging ,A

4member 50, when yextending along `one diagonal,V will cause a voltageof one polarity `to be induced in the sens ing line 32.. lf a bridgingmember extends alongthe opposite diagonal, asexempliiied by theVbridgingzmember 52, then when ya current pulse is applied to the line20,

a voltage of opposite polarity is induced in the line' 32.v

The sensing Icircuit 42 will detect this voltage.

tangular grid of grooves, a plurality of rst wires, a different oneofwhich is disposed 'in 'a diierent one 'of the grooves which extendsalong arst co-ordinate, a plurality Vof second wires,`a different one ofwhich is disposed along a different Yone, of the grooves which'extendalong a second `co-ordinate of said rectangular grid, said iirst andT-he memory Vwhich has been described l'has theI proporientation of thebridging membersrelative to a sensingV line. Also, nondestructivereadout is provided, That is, nomatter how often the dataiwhich isplacedV inthe erty that data storage therein'is .made-possibleby the`memory Ais sensed, it is notfdestroyed.A It' 'should be ap- Ypreoia-ted'that where `a substantially permanent type offstorage memory`desired, wherein data changes do not occur too often, this type [ofmemory is satisfactory.

However, where a rapid data change is desired, or whererfrequentchangesare desired, this memory hasfsome lim'-A itations.v 1 iFIGURE 3 is a view of an arrangement Vin accordance with this inventionfor solving the difculties of the memory whichha's just been described.The ferrite yplate 60,r

which is employed, is essentially theV same as the one described inconnection Ywith FIGURE l. A gridv of drive wires and sensing wires arealso disposed in the `grooves x in the same manner asis shown inFIGURE 1. Address-` ing circuits and sensing circuits identical withthose shown ;A with Vsaid sheet second wiresfcrossingone another at aplurality of intersections but not beingIriagneticallyV coupled to oneanother, said improvement comprising meansffor providing magneticVcoupling'at each of said intersectionsl comprising a sheet! ofnonmagnetic nc'nnc'onductive material VVpositioned adjacent to saidsheet of magnetic material plate, said sheet having'a plurality ofholes, each of said plurality lof holesl being ,disposed over adifferent one of said intersections of saidfrst and second wires, aplurality of magneticv material bridging members, and means forremovably holdinga :diierent one ofr said-bridging members withina-different one of the holesin said sheet wof vnonmagnetic materialdiagonally disposedA relative to an intersection of arst and second wireand in contact of magnetic material on both sides Aof said intersection.

2. The Vapparatus as recited in claim'l wherein each Saidmeans forholding a bridging member'of magnetic in FIGUREI may be employed withthis memory. These o are omitted from .FIGURE 3, to preserve clarity inthe drawings.

one of the openings 64 is positioned to permit access to A plastic plate62, Whichhas aff/plurality of openings 64, is placed on top Vof theferrite sheet 6 0. ,'Each j the region of a different one of theintersections o n the ferrite'sheet60.V -The plastic sheet 62l has aportionthereof removed to show thatthe grooveand wireV intersections lofthe underlying ferrite block 60 are substantially identi cal with thoseof the block 10. shown on FIGURE l.V

Into each one ofthe holes 64, V66, etc., in 'theffplastic sheet 62thereis inserted one of lthe'plugs, 70, shown in FIGURE. 'Each one ofthe plugs-70 has'anrend section isdisposed.I Y

. material in one of said aperturescornprises a plug dimensionedA to'tjwithin an aperture,fsaid plug being Ymade of nonmagnetic materiahand aslot at one end of said plug withinwhich said magnetic bridging. member3. A 'magnetic-memory', device comprising a'base of .y `magneticmaterial, a `plurality of parallel-spaced iirst grooves inV one surfaceof said baseya plurality of parallel-spaced secondngrooyesin said-onesurface of .said baseintersecting said-plurality of said rst grooves atVVsubstantially vrightangles, a plurality of sensing wires, a

different one o f'which is in andy extends along a different one of saidiirstV grooves,ja plurality offdriving wires, a

Vdifferent one ofwhich is-in and extends along'a different oneofgsaidrsecond grooves, said sensing anddriving 72, which isshapedto-accommodate a magnetic Vbridging l member 74.

Y Each onev of the sheets 62is prepared in advance. AInto f each one ofits openings there is inserted oneofthe plugs 70 holding a ferritebridging memberV 74. Each oneof the holes 64, as well as the top of eachof the Vplugs,"has markings so that the ferrite'b'r'idging members canbe prop- Vwires crossing one anotherV at substantially right angles andbeing insulated from one another, and means for storinginformation insaidrmagnetic rstorage device including asheet ofnonmagnetic:nonconductive material covering'said one surface, aplurality of openings in said Y sheet of Vnonmagneticmaterial each'oi:`which is'positioned erly oriented. For data entry, all that'is necessaryis, to .Y

bring one of the suitably prepared plastic sheets incontact' with theferrite plate. Any suitable clamping means, not

shown,'may be employed to h old the sheet in place.- When it is desiredto write other information into a memory;

preparedr plastic sheet, is substituted in its place. Alternatively,each one of the plugs may be turned to provide a signal representingeither a zero or arone bit whenthe drive line underneath is excited.Connection may be made to the drive and sense` lines on theplate in anythen the plastic sheet is removed and another, previously v the pathalong theA otherl diagonal.

suitable manner, suchas by direct solderconnections or by terminatingkthese linesinV conductiveA tabs or terminals `76, 7.8, .to whichconnection may be type of suitable contacting sockets. v

e There has accordingly been described 4and shown herein a novel,usefuLandimproved nondestructive-readout type of magnetic," memorywherein a bridging member which made lby any bridges the intersection of"two, orthogonally disposed'.r

wires determines the binary bit which is stored;Y The memory isr simpleto manufacture. Data entry may be accomplished in the entire memory atoncejby changing the plastic vsheetv holdingthe plugs `and bridgingmembers, or a bit iat a time by turning each plug individually'to,`assume the proper orienttiticgii.Vv i

" over a different oneofthelintersections of said plurality o fsaidrstand second grooves, ay plurality of plug means a different rone ofwhich is insertedwithin a different one of said plurality Ofapertures insaidnonmagnetic sheet, each of said plug means carryingameansforestablishing a magneticfuxpath across an intersectionof groovessubstantially alongfonediagonal which path "has a reluctance which islow'wh'en compared with the reluctance of4.1Amagnetic-storage,device'comprising a base of magnetic materiaLnarectangular grid of grooves onV the surface` of said base,.said groovesseparating lands`of materials, laV plurality of1 sensingvwires, adifferent one of Vwhich is in and extendsl along 'a vdifferent one rof`the grooves insaid rectangularfgrid"which are parallel to oneanother-,1a plurality of; driving wires. ay diif'er'ent one offwhich isin and extends'along a different one of the grooves in said rectangular;grid which arey aty right anglesy tothe grooveswherein saidsensing wiresare. disposed, said sensing, and driving wires crossing ,eachV yothersubstantially atv right angles aiidfbeing insulated from one another, anonmagnetic nonconductive .sheetjadjacent to said base offmag'neticmaterial andlextendingover. the

surface thereof, said nonmagnetic nonconductive sheet Vhaving aplurality o f openings therethrough .which are dis- 'posed to allor-'dlaccessto,teach of theintersections `of the grooves in said rectangulargrid, a plurality of plug members a different one of which is rotatablyinserted into a diierent one of said plurality of openings, each 0f saidplug members carrying a bridging member made of magnetic material, saidbridging member being positioned at the end of the plug member forcontacting diagonally opposed lands at an intersection of the grooves,said plug being rotatable for alfording a selection of the diagonalposition of the bridging member.

References Cited by the Examiner UNITED STATES PATENTS 2,825,891 3/58Duinker 340-174 3,027,548 3/62 Vaughan 340-174 3.061,821 10/62 Gribbleet al 340-174 3,102,999 9/63 Bernemyr et al 340-174 TRVING L. SRAGOW,Primary Examiner.

4. A MAGNETIC-STORAGE DEVICE COMPRISING A BASE OF MAGNETIC MATERIAL, ARECTANGULAR GRID OF GROOVES ON THE SURFACE OF SAID BASE, SAID GROOVESSEPARATING LANDS OF MATERIALS, A PLURALITY OF SENSING WIRES, A DIFFERENTONE OF WHICH IS IN AND EXTENDS ALONG A DIFFERENT ONE OF THE GROOVES INSAID RECTANGULAR GRID WHICH ARE PARALLEL TO ONE ANOTHER, A PLURALITY OFDRIVING WIRES A DIFFERENT ONE OF WHICH IS IN AND EXTENDS ALONG ADIFFERENT ONE OF THE GROOVES IN SAID RECTANGULAR GRID WHICH ARE AT RIGHTANGLES TO THE GROOVES WHEREIN SAID SENSING WIRES ARE DISPOSED, SAIDSENSING AND DRIVING WIRES CROSSING EACH OTHER SUBSTANTIALLY AT RIGHTANGLES AND BEING INSULATED FROM ONE ANOTHER, A NONMAGNETIC NONCONDUCTIVESHEET ADJACENT TO SAID BASE OF MAGNETIC MATERIAL AND EXTENDING OVER THESURFACE THEREOF, SAID NONMAGNETIC NONCONDUCTIVE SHEET HAVING A PLURALITYOF OPENINGS THERETHROUGH WHICH ARE DISPOSED TO AFFORD ACCESS TO EACH OFTHE INTERSECTIONS OF THE GROOVES IN SAID RECTANGULAR GRID, A PLURALITYOF PLUG MEMBERS A DIFFERENT ONE OF WHICH IS ROTATABLY INSERTED INTO ADIFFERENT ONE OF SAID PLURALITY OF OPENINGS, EACH OF SAID PLUG MEMBERSCARRYING A BRIDGING MEMBER MADE OF MAGNETIC MATERIAL, SAID BRIDGINGMEMBER BEING POSITIONED AT THE END OF THE PLUG MEMBER FOR CONTACTINGDIAGONALLY OPPOSED LANDS AT AN INTERSECTION OF THE GROOVES, SAID PLUGBEING ROTATABLE FOR AFFORDING A SELECTION OF THE DIAGONAL POSITION OFTHE BRIDGING MEMBER.